Roll coating machine



April 37 1934. c, mc u-r 1,955,414

ROLL COATING MACHINE Filed Oct. 8, 1931 ATTORNEY Patented Apr. 17, 1934 PATENT OFFICE ROLL COATING MACHINE Charles A. Dickhaut, Highland Park, N. J., as-

. signor to John Waldron Corporation, New

Brunswick, N. J., a corporation of New Jersey Application October 8, 1931, Serial No. 567,540

L 6 Claims.

This invention relates to roll coating machines. Various methods and apparatus have been used for the coating of papers, textiles and other mathe roll andin consequence the coating is applied indefinitely resulting in a streaky appearance. Smoothing rolls have been used to iron out the ridges left by the nip or coating roll but have been ineffective as the same ridges form on the smoothing roll and are redeposited by the leaving side of the roll. To overcome the streaking efiect or lining action the smoothing rolls have been positioned at an angle so that 10 the lines will be put back at a different point. The theory being that if a suificient number of lines are put back close enough together a uni- A form coating will be had. In practice, however, it hasbeen found impossible to accomplish the elimination of the streaking effect by the angling of the smoothing rolls. In order to reduce the streaking efiect it is necessary to brush out the lines by oscillating brushes. Under certain conditions the brushes are ineffective to eliminate streaking. In addition, they are a source of expense as they wear relatively quickly and cause excessive shutdowns due to the necessity of the brushes being frequently cleaned. The capacity of such a coating machine is-likew ise limited since the speed of the paper cannot exceed a certain speed. The brush must oscillate with a certain speed with respect to the speed of the paper and as there are mechanical limits on the brush oscillation speeds there are limits upon the speed of the travel of the paper. If the coating machine is operated in connection with a high temperature drier the stoppage of the machine to clean brushes, replace same or for any other purpose destroys the sheet of paper in the drier for commercial uses. Also any stoppage increases the labor cost as well as reducing the outlet. In addition to the difliculty in securing uniformity of appearance there is the further difficulty of applying a predetermined thickness of coating or predeterminedly varying the thickness.

One of the objects of this invention is to provide a roll coating machine adapted for coating material on one or both sides.

A further object of this invention is to apply a coating uniformly having a smooth, even appearance without streaking or lining.

A still further object of this invention is to easily control the depth of coating.

Still other objects of the invention are to increase the capacity of the machine by increasing the speed of coating and speed of travel of the material being coated and to reduce shutdowns by reason of brush trouble.

Referring to the drawing:

Figure 1 is a view in side elevation of a machine embodying the principles of my invention.

Figure 2 is a diagrammatic view of the nip or coating rolls and the smoothing rolls and coating removers cooperating therewith and showing the threading of the material around the rolls.

Figure 3 is a detail top plan view of the smoothing roll with the coating remover.

In carrying out my invention, 1 propose'to providea frame 1 supporting at one end unwind rolls "5 2 and 3 carried by shafts 4. and 5 in bearings 8 and '1 of frame 1. Friction brakes 8 and 9 cooperate with gears 10 and 11 on shafts 4 and 5 to control tension of the material being coated. Brakes Band 9 are automatically controlled by 80 floating tension roller 12. The shaft '13 of roller 12 is supportel in bearings 14 at each end thereof. Bearings 14 in turn aresupported by yokes 15 pivotally mounted in bracket 16. Connected to one of yokes 15 is lever 17 having a weight capable of being secured at difierent points on one arm 18 and having the other arm 19 slidably secured to rod 20 in order to rockrod 20 as roller 12 moves up or down. As arm 19 is rocked upwardly it bears against spring 21 to move rod 20 which rocks links 23, 24, 25, to rotate shafts 26, 27, to contract friction bands 28 upon drums 29 through links 30,- 30'. The rocking of arm 19 downwardly in the same manner through the samelinks rocks shafts 26, 2'7, to release friction bands 28. To increase or decrease the tension, movable weight 70 may be positioned to or from the fulcrum on arm 18. The paper or other material 31 after passing over idler supporting roll 32 and around floating tension roll 12 passes over idler roller 3 3 and between nip" or coating rolls 34, 35. Roll 35 picks up coating from pan 36 supported thereunder by frame 1 and applies it to the bottom of the material 31. Pan 36 may be supplied in any well known manner from a source of supply. As this is common practice for clarity the piping, pump and strainer are not shown. In the case of double coating a spray 3'1 floods the upper side of the sheet just before it enters the nip rolls 34, 35. Spray 3'7 is likewise no fed from the common source of supply or from pan 36 by a pump, or gravity. The material 31 then passes under smoothing roll 38 and over smoothing roll 39. The coated material 31 when it leaves the nip" or coating rolls 34, 35, is lined with fine ridges of color and as it passa beneath the smoothing roll 38 the latter smooths out the fine ridges and removes the excess coating. Beioretheexcuscoatingcanberedepositedby smoothing roll 38 upm the mterial 31 coating remover 40 removes said excess coating from smoothingroll 38. In other words, thereis a transfer of the ridge of excess material from the material being coated to the smoothing roll 38 and its removal before redqiositing while at the same time the smoothing roll smooths the coating on the material 31. The same action is repeated by roll 39 and coating remover 40' on the underside in the case of double coating. I have foundthatif Iapply aslightexcessofcoating at the nip" or coating rolls 34, 35, and adjust them with a slightly wider opening than is customary.

'thatIcancontrolthedepthof the coatingby rotating the rolls 38, 39, in a direction opposite to the direction of travel of material 31 and by controllim the speed of rotation of the smoothing rolls 38, 39. That is, the faster the rolls 38, 39, are caused to rotate the more coating is removed and the less depth of coating remains on material 31. I therefore propose to control the speed of rotation of rollers 38, 39, by a variable speed drive in any well known manner. I have shown one form of variable speed drive such asamotordrivenconepulleyflhaving shiftable belting 41, 43, to pulleys (not shown) on shafts 73, 74, of mils 38, 39.

By the use of the coating removers 40, 40', the coating which is picked up by rolls .38, 39, is cleaned off and the surfaces of rolls 38, 39, are always returned to material 31 smooth and clean, but at the same time slightly damp. I have found that the surface of rolls 38, 39, must be slightly damp for if the coating removers 40, 40', are adjusted so that the surfaces of rolls 38, 39,

are dried, material 31 will be streaked. A per-' fectly dry roll tends to pick up the coating unevenly while a damp roll smooths the coating and removes the ridges. The excess coating removed by coating removers 40, 40', runs oi! their ends into drip pan 44 which ,empties into pan 36. In order to prevent occasional hard particles in the coating catching and posibly wearing a groove in rolls 38, 39, or a nick in coating removers 40, 40', the coating removers may be oscillated in any well known manner such as the same mechanism used for oscillating the brmhes at a much slower speed.

After the material 31 leaves rolls 38, 39, it is evenly coated to the desired thickness on one or both sides and it then can be dried in any well known manner, preferably in a high temperature drier.

If the coating is not thoroughly or carefully mixed, occasional lumps or particles may'come through in the coating and form scratches. To eliminate such scratching, I prospose to provide two sets of oscillating brushes 50, 51, and to utilize one setatatimesothatifthebrushesin use need cleaning or attention the second set of brushes may be thrown in and the first set removed and cleaned or changed without stopping the machine. This is especially desirable in high speed coating and high temperature drying as the mach'ne cannot be'stopped for.any length,

oftimeasthewilloverdryandspoil the sheet. As brushes 50, 51, are not required to eliminate streaking or lin ng, the capacity of the machine is not limited by their oscillation speed. The reduction of the oscillation speed of the brushes and the elimination of brush troubles and shut downs by reason thereof the capacity of the machine without reference to the increased speeds that may be utilized. Nip or coating rolls 34, 35, are of the usual type and are arranged in the usual manner having shafts 52, 53, in bearing blocks 54, 55, carried in channels 56 in frame 1. Adjustment screws 57, 58, permit of adjustment of the distances between the "nip" rolls 34, 35. Hand operated lever 59 permits of a raising of the upper roll 34 for easy cleaning or insertionof the material. I preferably drive th'evarious elements by separate motors. This permits of separate control of the different elements. For instance, motor 67 drives the cams for oscillating linkage 68 for the br shes 50, 51, and may drive similar oscillating linkage 60 for coating removers 40, 40'. Motor 69 drives cone pulley 42 which in turn drives through shiftable belting smoothing rolls 38, 39. Motor 78 drives through belting 71, 71', nip" rolls 34, 35, through belting 71, 71'.

It will thus be seen that I have invented a roll coating machine which permits of high speed operation in large capacity and wherein the coating is applied uniformly without streaking and whereby the depth of coating may be controlled with the elimination of the use of brushes except in an auxiliary capacity thereby reducing brush troubles to a minimum.v It will further be seen that I have invented a roll coater of increased efliciency permitting of cheaper manufacture of coated paper.

What I claim is:

1. In a coating machine, means for applying an excess coating to the material to be coated and a smoothing roll, means for removing said excess of coating material by the smoothing roll and means for removing said excess from the smoothing roll during each revolution of the smoothing roll and means for moving said removing means parallel to the surface of the smoothing roll to prevent lodgment of particles of coating material between said surface of the smoothing roll and said coating remover.

2. In a coating machine, means for applying an excess coating to the material to be coated and a smoothing roll, means for removing said excess of coating material by the smoothing roll and means for removing said excess from the smoothing roll during each revolution of the smoothing roll and means for moving said removing means parallel to the surface of the smoothing roll to prevent lodgment of particles of coating material between said surface of the smoothing roll and said coating remover, and means for brushing out any scratches'in the coating 'by reason of the temporary lodgment of a dry particle of coating material between said smoothing roll and coating remover.

3. In a coating machine, means for applying an excess coating to a travelling web, a smooth hard polished surface roll running in the reverse direction to the web to remove the ridges and excess color from the web, a thin flexible doctor to remove the excess color from the surface of the reverse turning ro11,\means for rotating said reverse turning roll at a variable speed relative to said web.

4.;In a coating machine, means for applying an excess coating to a travelling web, a smooth hard surface reverse turning roll to remove the ridges and excess color, a thin flexible doctor to remove the excess color and clean the surface of the reverse turning roll, means for rotating the said reverse turning roll at a lesser peripheral speed than the linear speed of the web.

5. In a coating machine, means for simultaneously applying an excess coating to both sides of a travelling web, a smooth polished surface roll on each side of the web and rotating in the reverse direction to the direction of travel of the web to remove the ridges and excess color from the web, a thin flexible doctor for removing the excess color and cleaning each of said rolls and means for varying the relative speed of the said rolls.

6. In a coating machine, means for simultaneously applying an excess-coating to both sides of a travelling web, a smooth hard surface reverse turning roll on each side of the web to remove the excess color from each side of the web, a thin flexible doctor for removing the excess and cleaning each of said reverse turning rolls and means for rotating each of said reverse turning rolls at a lesser peripheral speed than the linear speed of the said web.

CHARLES A. DICKHAUT. 

